Pleural Effusion

Definitions

- What Is Pleural Effusion ?

• Pleural effusion results from fluid accumulating in the potential space between the visceral and parietal pleurae When there is an imbalance between formation and absorption in various disease states , in response to injury , inflammation, or both locally and systematically .

More Definitions ?

• Parapneumonic Effusion : pleural effusion associated with bacterial pneumonia, bronchiectasis, or lung abscess .

• Complicated Parapneumonic Effusion : refers to parapneumonic effusions that require tube thoracostomy for their resolution .

• Loculated Effusion : Fluid anatomically confined and not freely flowing in the pleural space when there are adhesions between the visceral and the parietal pleura .

• Sub-Pulmonic Effusion: accumulation of fluid between the lung & the diaphragm which gives the false impression of an elevated hemi-diaphragm

Normal Physiology

• Up to 25 ml of pleural fluid is normally present in the pleural space which is an amount not detectable on conventional chest radiographs , and is secreted from the parietal pleura into the pleural space where it is absorbed by the visceral pleural microcirculation, and lymphatics .

• This small amount of pleural fluid reduces friction between the pleural layers and allows for smooth lung expansion and contraction with respiration.

Normal Physiology

• Under normal circumstances, the direction of pleural fluid flow is largely governed by the difference in hydrostatic pressure between the systemic and the pulmonary circulations

• Pleural fluid exists in a dynamic equilibrium in which influx equals efflux, with approximately 1 L of fluid traversing the pleural space in 24 hours.

• So pleural effusion develops whenever influx of fluid into the pleural space exceeds efflux.

• Normal amount 8.4 ml per hemithorax with a WBC count of 1700 per ml 75% of which are neutrophils and 23% lymphocytes. Protein concentration is low about 15% of plasma protein concentration. There is no RBCs

Pathophysiology

Rate of Fluid Rate of FluidAccumulation Removal

1. Altered Pleural Membrane Permeability2. Decreased Intravascular Oncotic Pressure3. Increased Capillary Hydrostatic Pressure4. Lymphatic Obstruction5. Abnormal Sites of Entry

Excess protien

Pathophysiology

• Pulmonary Capillary Pressure (CHF)

• Capillary Permeability (Pneumonia)

• Intrapleural Pressure (Atelectasis)

• Plasma Oncotic Pressure (Hypoalbuminemia)

• Pleural Membrane Permeability (Malignancy)

• Lymphatic Obstruction (Malignancy)

• Diaphragmatic Defect (Hepatic Hydrothorax)

• Thoracic Duct Rupture (Chylothorax)

Pleural effusion has several origins :

Causes ?

• These Are The Most Common :

- Congestive Heart Failure (CHF)- Malignancy

- Bacterial Pneumonia- Pulmonary Embolism

- TB

Other Causes & Associates ?• Cirrhosis • Ascites• Peritoneal dialysis• Nephrotic syndrome• All kinds of infections of the lung parenchyma or pleura ( B , V , F , P )• Uremia• Myxedema• Ovarian hyperstimulation syndrome• Collagen vascular diseases ( SLE , RA )• Intra-abdominal processes ( Acute pancreatitis, subphrenic abscess) • Esophageal perforation • Bacterial pneumonia with parapneumonic effusion • Post Chemo-Radiotherapy• Drug-related : Amiodarone, Nitrofurantoin , Dantrolene ,

Methysergide , Bromocriptine , Procarbazine • Lung & breast cancer • Lymphoma• Meigs syndrome .• Psuedocyst . • Mesothelioma • SVC syndrome• Yellow-nail syndrome

• Diaphragmatic hernia• Post abdominal surgery • Endoscopic variceal sclerotherapy • Post liver transplant• Immunoblastic lymphadenopathy • Sjögren's syndrome • Wegener's granulomatosis• Churg-Strauss syndrome• Post-coronary artery bypass surgery • Asbestos exposure • Sarcoidosis• Trapped lung • Radiation therapy • Post-cardiac injury syndrome • Hemothorax • Iatrogenic injury • Pericardial disease • Chylothorax• Urinothorax• Postpartum• Glomerulonephritis

Types ?– Transudate : result from an imbalance between hydrostatic (e.g.,

CHF) and oncotic (e.g., nephrotic syndrome) pressures. This imbalance results in the production of an ultrafiltrate with low protein content across the pleural membrane.

– Exudate : result from pleural disease, usually inflammation or neoplasia, that results in active fluid secretion or leakage with high protein content.

– Empyema : Requires the presence of bacteria on Gram’s staining of the pleural fluid.

– Hemothorax & Chylothorax : From rupture of the thoracic duct are special instances of pleural effusion

Types ?Transudate Exudate

Congestive heart failure Infections

Cirrhosis with ascites bronchiectasis

Nephrotic syndrome Lung abscess

Hypoalbuminemia Tuberculosis

myxedema Neoplasms

Peritoneal dialysis Lymphoma

glomerulonephritis

Supperior vena cava obstructionPulmonary embolism

Types ?• Some pleural effusions can present as either transudates or exudates

or may have characteristics of both. In the case of pulmonary embolism, the pathogenesis of pleural effusion is often multifactorial, reflecting increased pulmonary vascular pressure (a transudative process) and ischemia and breakdown of the pleural membrane (an exudative process).

• Massive effusions (>1.5–2 L) are most commonly associated with malignancy but also can arise in the setting of congestive heart failure, cirrhosis, and other conditions.

Transudates Vs. ExudatesLight’s criteria for differntiating transudates from exudates

Plueral fluid considered an exudate if one or more of the following is true

1. Plural fluid protein level : serum protein level > 0.5

2. Pleural fluid Lactate dehyrogenase LDH level : serum LDH level > 0.6

3. Pleural fluid LDH level > 2/3 * upper limit of normal for serum LDH level

Clinical Features

• History :– Dyspnea– Pleuritic chest pain– Cough – Fever– Hemoptysis– Wt. loss– Trauma– Hx. of cancer– Cardiac surgery

• Physical :– Dullness to percussion– Decreased breath sounds– Absent tactile fremitus– Other findings: ascites,

JVP, peripheral edema, friction rub, unilateral leg swelling

Clinical Features• Symptoms associated with pleural effusion are most often due to the

underlying disease process and not the effusion itself.

• Small pleural effusions can be entirely asymptomatic.

• A new pleural effusion may be heralded by localized pain or pain referred to the shoulder.

• When the volume of pleural fluid reaches 500 mL, dyspnea on exertion or at rest may occur as a result of compromised pulmonary function.

• Egophony and enhanced breath sounds can often be appreciated at the superior border of the effusion because of underlying atelectatic lung tissue.

Clinical Features

• Distended neck veins, an S3 gallop, or peripheral edema suggests >>>> CHF

• A right ventricular heave or thrombophlebitis and sinus tachycardia suggests >>>> PE

• The presence of lymphadenopathy or hepatosplenomegaly suggests >>>> Cancer

• Ascites may suggests >>>> end stage liver disease

• Signs of consolidation above the level of the fluid in a febrile patient suggests >>>> Parapneumonic Effusion.

Diagnosis

Diagnosis

Role Of Chest X-Rays

- Detection and the differential diagnosis are highly dependent upon imaging of the pleural space.

- Conventional radiographic methods used are frontal, lateral, oblique and decubitus radiographs.

- Blunting of either costophrenic angle is indicative of the accumulation of between 250 - 500 ml of fluid

- 1000 ml of effusion reaches the level of the fourth anterior rib

- Because of gravity, fluid accumulates in subpulmonic location .

Diagnosis

Diagnosis

Role of CT scan– Visualization of underlying lung parenchymal processes

that are obscured on chest radiographs by large pleural effusions

– Very Sensitive

– Can distinguish between Lung Abscess & Empyema

– On decubitus radiographs and CT scans, less than 10 mL, and possibly as little as 2 mL, can be identified

Diagnosis

Diagnosis

Role of Ultrasonography

– Free vs loculated pleural effusions, and loculated effusions vs solid masses.

– Thoracentesis of loculated pleural effusions is facilitated by ultrasound marking or guidance.

– Helpful in Confirming the Presence of a Small Pleural Effusion.

Diagnosis

Diagnosis

Role of MRI

– Can display pleural effusions, pleural tumors, and chest wall invasion.

Diagnosis

Diagnosis

Diagnostic Thoracentesis- An unexplained pleural effusion requires further investigation. Unless

required to rule out an immediately life-threatening condition such as empyema or hemothorax, pleural fluid evaluation may be deferred to an inpatient or outpatient setting.

- No need for thoracentesis for patient with obvious cause may not need further study (CHF with bilateral effusions) .

- Indicated if the effusion is clinically significant with no known cause.

Diagnosis

• Also indicated in a patient with CHF if any of the following are present.

A unilateral effusion, particularly if it is left-sided, Bilateral effusions, but are of disparate sizes There is evidence of pleurisy or feverThe cardiac silhouette appears normal on CXR If no response to diuresis in 48-72 hrs.The alveolar-arterial oxygen gradient is widened out

of proportion to the clinical setting

DiagnosisContraindications :

- None Absolute.

- Relative include :

• Patient on anticoagulation or with bleeding diathesis

• Very small volume of fluid.

• Patients on mechanical ventilation are at high risk for tension pneumothorax.

• Active skin infection at the port of entry.

Diagnosis• Post procedure CXR :

- Indicated only if air is obtained during the procedure or if cough, pain or dyspnea develops.

• Complications :

- Pain >>> Give Pain Medications NSAIDs Sometimes Opiods - Bleeding (hematoma, hemothorax, or hemoperitoneum) >>> Fluids - Pneumothorax >>> Multi-Dependence - Empyema >>> Sterility - Soft tissue infection >>> Sterility - Spleen or liver puncture >>> Ultrasound Guided - Vasovagal events >>> Multi-Dependence . - Adverse reactions to lidocaine or topical antiseptic solutions >>> Ask About it

Diagnosis

Thoracentesis: Transudate vs. Exudate

1. Gross Appearance2. Cell Count & Differential3. Gm Stain, C & S4. Cytology5. LDH6. Protein7. Glucose, Amylase

Appearance

- Bloody : Cancer, PE, Trauma, Pneumonia.

- Turbid : either due to cells or debris or a high lipid level.

- Putrid Odor : Anaerobic infection

- Ammonia Odor : Urinothorax

a bloody pleural effusionoccurring in a patient without a history of trauma

or pulmonary infarctionis

Indicative of Neoplasm in 90 % of cases!

• A True Hemothorax is when the Pleural Fluid Hct exceeds 50 % of the Peripheral Blood Hct !

• Beware Of Aortic Aneurisms !!!

Treatment

• Transudative Effusion : focus on the systemic cause , rule out a diagnosis of congestive heart failure,

cirrhosis, or pulmonary embolism.

• Exudative Effusion : dependent on the exact sub-type , send for total and differential cell counts, smears

and cultures for organisms, measurement of glucose and lactate dehydrogenase levels, cytologic analysis, and testing for a pleural-fluid marker of tuberculosis.

• Consider Chest Thoracostomy • Gross Pus / Empyema• pH < 7.2• Hemothorax• Complicated Parapneumonic Processes• Malignant Effusions…but remember the role of pleurodesis!

PORCEL et al. AFP 2006; 73: 1212

Other Pleural Fluid Tests

PORCEL et al. AFP 2006; 73: 1212

Other Pleural Fluid Tests

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